From: Dan Murphy <dmurphy@ti.com>
To: <jacek.anaszewski@gmail.com>, <pavel@ucw.cz>
Cc: <linux-leds@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
Dan Murphy <dmurphy@ti.com>
Subject: [PATCH v6 2/9] documention: leds: Add multicolor class documentation
Date: Tue, 17 Sep 2019 12:59:30 -0500 [thread overview]
Message-ID: <20190917175937.13872-2-dmurphy@ti.com> (raw)
In-Reply-To: <20190917175937.13872-1-dmurphy@ti.com>
Add the support documentation on the multicolor LED framework.
This document defines the directores and file generated by the
multicolor framework. It also documents usage.
Signed-off-by: Dan Murphy <dmurphy@ti.com>
---
v6 - Removed color_mix and color_id files
Documentation/leds/index.rst | 1 +
Documentation/leds/leds-class-multicolor.rst | 101 +++++++++++++++++++
2 files changed, 102 insertions(+)
create mode 100644 Documentation/leds/leds-class-multicolor.rst
diff --git a/Documentation/leds/index.rst b/Documentation/leds/index.rst
index 060f4e485897..bc70c6aa7138 100644
--- a/Documentation/leds/index.rst
+++ b/Documentation/leds/index.rst
@@ -9,6 +9,7 @@ LEDs
leds-class
leds-class-flash
+ leds-class-multicolor
ledtrig-oneshot
ledtrig-transient
ledtrig-usbport
diff --git a/Documentation/leds/leds-class-multicolor.rst b/Documentation/leds/leds-class-multicolor.rst
new file mode 100644
index 000000000000..d34feeb61284
--- /dev/null
+++ b/Documentation/leds/leds-class-multicolor.rst
@@ -0,0 +1,101 @@
+====================================
+Multi Color LED handling under Linux
+====================================
+
+Description
+===========
+There are varying monochrome LED colors available for application. These
+LEDs can be used as a single use case LED or can be mixed with other color
+LEDs to produce the full spectrum of color. Color LEDs that are grouped
+can be presented under a single LED node with individual color control.
+The multicolor class groups these LEDs and allows dynamically setting the value
+of a single LED or setting the intensity values of the LEDs in the group and
+updating the LEDs virtually simultaneously.
+
+Multicolor Class Control
+========================
+The multicolor class presents the LED groups under a directory called "colors".
+This directory is a child under the LED parent node created by the led_class
+framework. The led_class framework is documented in led-class.rst within this
+documentation directory.
+
+Each colored LED is given its own directory. These directories will be one of
+LED_COLOR_ID_* definitions from the header include/dt-bindings/leds/common.h.
+Under these directories the intensity and max_intensity files are presented for
+each LED.
+
+Directory Layout Example
+========================
+root:/sys/class/leds/rgb:grouped_leds# ls -lR colors/
+colors/:
+drwxr-xr-x 2 root root 0 Jun 28 20:21 blue
+drwxr-xr-x 2 root root 0 Jun 28 20:21 green
+drwxr-xr-x 2 root root 0 Jun 28 20:21 red
+
+colors/blue:
+-rw------- 1 root root 4096 Jun 28 20:21 intensity
+-r-------- 1 root root 4096 Jun 28 20:27 max_intensity
+
+colors/green:
+-rw------- 1 root root 4096 Jun 28 20:22 intensity
+-r-------- 1 root root 4096 Jun 28 20:27 max_intensity
+
+colors/red:
+-rw------- 1 root root 4096 Jun 28 20:21 intensity
+-r-------- 1 root root 4096 Jun 28 20:27 max_intensity
+
+Multicolor Class Brightness Control
+===================================
+The multiclor class framework will calculate each monochrome LEDs intensity.
+
+The brightness level for each LED is calculated based on the color LED
+intensity setting divided by the color LED max intensity setting multiplied by
+the requested value.
+
+led_brightness = requested_value * led_color_intensity/led_color_max_intensity
+
+Example:
+Three LEDs are present in the group as defined in "Directory Layout Example"
+within this document.
+
+A user first writes the color LED brightness file with the brightness level that
+is necessary to achieve a blueish violet output from the RGB LED group.
+
+echo 138 > /sys/class/leds/rgb:grouped_leds/red/intensity
+echo 43 > /sys/class/leds/rgb:grouped_leds/green/intensity
+echo 226 > /sys/class/leds/rgb:grouped_leds/blue/intensity
+
+red -
+ intensity = 138
+ max_intensity = 255
+green -
+ intensity = 43
+ max_intensity = 255
+blue -
+ intensity = 226
+ max_intensity = 255
+
+The user can control the brightness of that RGB group by writing the parent
+'brightness' control. Assuming a parent max_brightness of 255 the user may want
+to dim the LED color group to half. The user would write a value of 128 to the
+parent brightness file then the values written to each LED will be adjusted
+base on this value
+
+cat /sys/class/leds/rgb:grouped_leds/max_brightness
+255
+echo 128 > /sys/class/leds/rgb:grouped_leds/brightness
+
+adjusted_red_value = 128 * 138/255 = 69
+adjusted_green_value = 128 * 43/255 = 21
+adjusted_blue_value = 128 * 226/255 = 113
+
+Reading the parent brightness file will return the current brightness value of
+the color LED group.
+
+cat /sys/class/leds/rgb:grouped_leds/max_brightness
+255
+
+echo 128 > /sys/class/leds/rgb:grouped_leds/brightness
+
+cat /sys/class/leds/rgb:grouped_leds/max_brightness
+128
--
2.22.0.214.g8dca754b1e
next prev parent reply other threads:[~2019-09-17 17:57 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-17 17:59 [PATCH v6 1/9] leds: multicolor: Add sysfs interface definition Dan Murphy
2019-09-17 17:59 ` Dan Murphy [this message]
2019-09-17 17:59 ` [PATCH v6 3/9] dt: bindings: Add multicolor class dt bindings documention Dan Murphy
2019-09-17 17:59 ` [PATCH v6 4/9] dt-bindings: leds: Add multicolor ID to the color ID list Dan Murphy
2019-09-17 17:59 ` [PATCH v6 5/9] " Dan Murphy
2019-09-17 17:59 ` [PATCH v6 6/9] leds: multicolor: Introduce a multicolor class definition Dan Murphy
2019-09-18 17:09 ` Dan Murphy
2019-09-18 19:56 ` Greg KH
2019-09-18 21:27 ` Jacek Anaszewski
2019-09-19 1:07 ` Dan Murphy
2019-09-19 21:32 ` Jacek Anaszewski
2019-09-20 12:31 ` Dan Murphy
2019-09-17 17:59 ` [PATCH v6 7/9] dt: bindings: lp50xx: Introduce the lp50xx family of RGB drivers Dan Murphy
2019-09-17 17:59 ` [PATCH v6 8/9] leds: lp50xx: Add the LP50XX family of the RGB LED driver Dan Murphy
2019-09-17 17:59 ` [PATCH v6 9/9] leds: Update the lp55xx to use the multi color framework Dan Murphy
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